Abstract:Bolt support is a common means in tunnel construction, and with the increasing complexity of working conditions, the combined structure of bolt and surrounding rock is also subjected to various dynamic loads. In the past, there are many researches on the mechanical characteristics of single bolt in tunnel, but there are few researches on the dynamic characteristics of the combination of bolt and surrounding rock. In this paper, the overall analysis of the bolt-surrounding rock structure, a simplified roadway roof bolt-supporting model, combined with the dynamic double beam theory, established and solved the model dynamics equation; MATLAB software was used for numerical simulation to study the natural vibration characteristics of the structure under different supporting parameters and the dynamic response under the external load, and the vibration reduction measures were proposed. The results show that the dynamic characteristics of rock bolt-surrounding rock structure are related to the length of anchor segment, the distance between bolts and the diameter of bolts. In the model established in this paper, the dynamic response of the structure decreases obviously with the proper increase of anchorage length and bolt spacing. With the change of bolt diameter, the dynamic characteristics of the structure are complicated, and the dynamic response of different parts of the structure varies greatly.